>>Long runs would be more prone to get sleepers.
Hours of service laws are designed to allow crews their rest.
It was 16 hours limit in my time in the late 60s; I think it is
12 hours presently.
Well on top of that, is that a crewman could end up getting called at any hour of the day or night. They have regulations for rest time, but not for disruption of circadian rhythms, with which some people do better than others. The guy may be rested up to the extend required by law but due to circadian rhythm he may be up when his body is still saying “I should be sleeping.”